


can you keep a secret?

by yellowjun



Category: TOMORROW X TOGETHER | TXT (Korea Band)
Genre: Anal Sex, Best Friends Huening Kai & Kang Taehyun, Bottom Huening Kai, Creampie, M/M, Plot What Plot/Porn Without Plot, Shameless Smut, Teacher-Student Relationship, Top Choi Soobin, Underage Sex
Language: English
Status: Completed
Published: 2020-08-04
Updated: 2020-08-04
Packaged: 2021-03-06 03:07:26
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 4,025
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25706389
Author URL: https://archiveofourown.org/users/yellowjun/pseuds/yellowjun
Summary: Having sex with his teacher was risky– it meant a one-way ticket to the principal's office and a 100% guarantee that Soobin would lose his job.But, regretfully so, that was exactly what made it so exciting.–Soobin fucks his student– Hueningkai.
Relationships: Choi Soobin/Huening Kai
Comments: 40
Kudos: 248





	can you keep a secret?

**Author's Note:**

> ⚠️ ATTENTION ⚠️
> 
> If you are uncomfortable with any of the TXT members being sexualized in any way, shape, or form, please do not read this work. I will not hesitate to delete your comment if you start spewing out hatred at me for writing this. Please kindly move on and don't waste your breath. Thank you!🤗

"So what if I have a crush on Mr. Choi?" Hueningkai spoke. "I don't think that's anything bad. Aren't teacher crushes supposed to be normal?"

Taehyun rolled his eyes, scoffing at the  _ absurdity  _ of this guy. 

"Teacher crushes  _ are _ normal, Hueningie. But you wanna know what's  _ not?"  _ He didn't give Hueningkai any time to answer his rhetorical question, simply cut him off before he could even say a word in response, "Walking out of Mr. Choi's classroom with hickeys on your neck every time he asks you to stay after school."

Hueningkai's mouth formed a faint 'o' shape. He immediately shrunk, averting his friend's gaze as he subconsciously touched his neck, "They're not hickeys.. they're, uh– bug bites!" He chuckled nervously, "Y-yeah he's got bugs in his classroom. They like to bite a lot. Especially on the neck." 

Taehyun blinked, not buying Hueningkai's excuse in the slightest. He shifted his weight onto his left foot, placing his hands on his hips as he spoke slowly. "Ahhh..  _ bugs, _ huh?" 

The redhead nodded to himself, poking the inside of his cheek with his tongue in an act of blatant annoyance.

"I didn't know  _ bugs _ could leave cum stains all over someone's pants."

"What?" Hueningkai panicked, eyes blown wide as he hurriedly ran his hands all over his pants, frantically trying to search for the cum stain Taehyun was talking about, looking up to face his friend once he was greeted with nothing. 

Taehyun looked disappointed, Hueningkai noted– disapproving of what he'd just done.

"I was kidding." Taehyun deadpanned. "You don't have anything on you. But seeing as how you reacted, it definitely seemed like you were rather worried about finding something." He quirked an eyebrow, slightly leaning towards Hueningkai. His voice was low as he whispered, backing him up against a locker, "Tell me.. just  _ what _ do you and Mr. Choi do everyday after sch–"

"Nothing!" Hueningkai quickly blurted out, causing Taehyun to slightly jump back in surprise. The tiles below him squeaked as his shoes skid against them. "We don't do anything!"

Taehyun scoffed in apparent disbelief, shaking his head. "You're not fooling me, you think I don't know how you get all those perfect scores for tests you never study for? Or how I almost  _ never  _ see you paying attention in class, yet you  _ still _ somehow always manage to get good grades?" 

Taehyun's wide eyes were narrowed at this point; he was getting heated. "You don't study and you don't put in any effort during school. I'm not _dumb_ Hueningkai, don't think I haven't noticed the way Mr. Choi looks at y–"

"I have no idea what you're talking about," Hueningkai interrupted for the nth time, cutting off his best friend before he could rant any further, "no clue at all. Hueningie is innocent, thank you very much."

Taehyun made a face. 

"You're lying." He spat, his voice laced with small sparks of sizzling anger and frustration, "I've known you for years, every time you speak in third person it means you're not telling the tru–"

"Now if you excuse me," The pale boy ignored Taehyun's comment once again, "I got, uh.. some more, um– tutoring to attend to with Mr. Choi."

"Since when did teachers give tuto–"

"I'll see you later, Taehyunie!"

"Wait, no–  _ Hueningkai!"  _ Taehyun groaned loudly, stomping his foot on the ground as he helplessly watched his friend quickly flee– watched as he made his way into a familiar blue haired teacher's classroom.

* * *

  
  


Soobin sat at his desk, back rested against his chair. Hueningkai was plopped atop his lap, shamelessly grinding down onto his teacher's hard on.

"Hyung.." He spoke softly, running his fingers through the older man's hair, "..can you stop leaving hickeys on me from now on?"

Soobin quirked an eyebrow, the corners of his mouth tugging into a slight frown– to which Hueningkai quickly elaborated.

"It's cause," He began, and his voice was  _ barely  _ above a whisper, "..I think Taehyunies catching on." 

"Catching on to what?" Soobin questioned with the same quiet tone Hueningkai used, cocking his head to the side in apparent confusion. "To us?"

Hueningkai nodded, dropping his gaze into Soobin's Adam's apple. He watched it move up and down as he gulped, raising his voice ever so slightly. 

"Yeah.. to  _ us." _

Soobin sat still for a second, looking into Hueningkai's doe eyes. He briefly thought about his relationship with the young student, thinking about all the trouble he could get himself into if anyone were to ever find out about them.

He wondered– just for a  _ split  _ second– if the risk was even worth it. 

(but then he caught a small glimpse of hueningkai's awkward little smirk and suddenly it all came tumbling back to him.)

"Let him find out." Soobin said with a smile– it was tight; forced. "He won't do anything now, will he? Taehyun is a smart boy, I'm sure he won't go around telling anyone about you and I if he lacked any concrete evidence," He nuzzled into the crook of Hueningkai's neck, humming contently, "that'd just be silly."

The younger boy frowned, not entirely put at ease. "But Taehyunie is bold.. what if he goes and does it anyway?"

"He won't, baby– we'll be fine."

Hueningkai frowned, pulling Soobin away from his neck once he felt the older man start to lick around his pale skin that held week-old love bites, "Fine, I believe you– but still, no more hickeys."

Soobin sulked, pouting. "But I  _ like  _ giving you hickeys.." He whined like a stubborn child, about to bury himself deep into the younger boy's neck once more before he was abruptly stopped by the palm of Hueningkai's hand.

"Too bad," He said, moving his hands away to place them onto Soobin's broad shoulders for leverage, "I'm not gonna risk it– especially now that I know I'm being way too obvious about my relationship with you."

Soobin furrowed his brows in distaste, swiftly snaking his hands so that they rested against the underside of Hueningkai's ass. He gave his butt a gentle squeeze, instilling a soft whimper from the younger boy.

"C'mon.." Soobin mumbled, eyeing the way Hueningkai's chubby cheeks turned a dusty pink, "..please? I'll give you a free hundred tomorrow on a test grade if you let me."

"You.." The young boy faltered slightly, "..you'd give me a free hundred even if I  _ didn't  _ let you." 

"Wanna test that?" Soobin teased, grinding his boner up onto Hueningkai's ass. "If you see a failing grade on your report card, you'll know why."

Hueningkai moaned. "H-hyung.."

Soobin looped his thumbs onto the hem of the latter's pants, tugging them down slightly.

"You still got your buttplug in, Hueningie? Or did you take it out while in between classes?"

Hueningkai bit his lower lip, squirming around as he answered shyly, "..I still have it in."

"Good boy." The blue haired teacher mumbled, planting a soft kiss onto the side of the student's neck, making Hueningkai's stomach flutter.

"Now, take off your clothes. You know what to do next."

* * *

  
  


The sound of skin slapping against skin could be heard from  _ miles  _ away.

Hueningkai's upper body was sprawled across Soobin's desk, his pants hastily pulled down to his ankles as he was mercilessly being thrusted into by his teacher's cock. Loud moans filled the room, lewd noises bouncing off the walls of the empty classroom the pair of love birds resided in.

"Ugh, fuck.." Soobin groaned, kneading Hueningkai's ass in his large hands, "..I almost forgot just how tight you felt, Hueningie."

"H-hyung, mm–" Hueningkai whimpered, blunt fingernails clawing at the desk beneath him in an attempt to recompose himself– though the blatant feverish state he was in and the way he kept mewling and fidgeting around was more than enough to alert Soobin about just how  _ needy  _ he was.

"Desperate, huh?" 

Hueningkai whined, lips quivering as he tried to speak amongst the overwhelming way Soobin was fucking him. His hands were shaky, his legs were trembling, Soobin was hitting all the right spots; it felt  _ heavenly. _

"It's– mmh– it's just b-been so long since we last had sex.."

Soobin quirked an eyebrow, licking his lips as he chuckled. It was low; deep. It sent shivers throughout Hueningkai's entire body, making his cock twitch and rub against his teacher's desk, pre cum messily staining the antique piece of furniture in the process, but the young boy didn't care– not when his teacher's dick was filling him up so nicely.

"My gum," He spoke, tone ever so tantalizing as he slowly ran his hands up and down the latter's naked back, "I fucked you yesterday.."

"..Did you forget already?" He added, and Hueningkai could practically hear the shit eating grin that was laced in his voice, "Was it _that_ good?"

_ "Hyuuuung.."  _ Hueningkai whined at Soobin's relentless teasing, squirming beneath his frame, pushing his ass further onto the older man's cock in an attempt to get him to stop talking– in an attempt to avoid hearing Soobin's calm, soothing voice speak the most absurd obscenities.

He could  _ feel  _ his tummy starting to develop that familiar warmth– the one that was sure to make him see stars, but he didn't want to cum that fast. Not when he knew he could last much longer. If only Soobin would just stop.  _ Talking. _

But Soobin didn't get the hint. And if he did– he simply chose to ignore it. Because where was the fun in giving hueningkai what he wanted when he could just watch him fall apart right in front of him instead?

He smirked, briefly leaning down to give Hueningkai a peck on the cheek. It was squishy; warm, stained with trails of dry tears– a telltale sign that he was having a hard time trying to keep it together. 

(it was truly a sight to behold and cherish, and soobin was positive– extremely so– that the very lewd and vibrant image of hueningkai messily sprawled atop of his desk was going to be plaguing his mind for  _ days  _ to come.)

"It's alright, Hueningie," Soobin murmured, fixing his posture as he pulled the student closer to him by his waist, eliciting a choked out moan from Hueningkai, feeling his teacher's cock fully enter him to the hilt in one swift motion, "I know just how–"

_ "Mr. Choi?" _

Soobin froze.

Hueningkai stilled.

And the deafening silence that quickly enveloped the two was nothing short of dreadful.

Hueningkai gulped. He recognized that voice anywhere; he had  _ just  _ heard it a while ago before he'd managed to barge into Soobin's classroom unannounced.

_ "Mr. Choiiii?"  _ It spoke out again,  _ "It's Taehyun. I've got some questions to ask you about the assignment you gave our class.. I'm, uh, I'm kinda confused about it? I don't know if I really understood today's lesson and Hueningkai said you were holding tutoring sessions soooo.."  _ he paused briefly, scratching his head, _ "..I felt like this would've been the perfect opportunity for me to ask if you could tutor me as well, if that's alright with you." _

Soobin cursed under his breath, eyeing Hueningkai and the way panic quickly etched itself onto his adorable set of features.

The older man tried his best not to moan, feeling Hueningkai clench around his cock. He sucked in a breath, unsure if his gum was purposely aiming to be a tease or if he was just legitimately tense– but whatever the reason may have been, he had to admit– even in the midst of a potential career ending predicament, Hueningkai still somehow managed to be overwhelmingly endearing.

"..Tutoring sessions? _ "  _ Soobin whispered, holding back a groan of disbelief. The  _ absurdity  _ of the excuse almost made him want to roll his eyes,  _ "Really?" _

Hueningkai blushed, the tips of his ears turning a cherry red as he hid his face in his hands, "..It's– I p-panicked and came up with it on the spot.." he mumbled and stuttered his way past a response, "..I'm sor–"

_ "Mr. Choi! I know you're in there, I can hear you and Hueningkai!"  _ Taehyun huffed from behind the classroom door,  _ "Hueningie, tell Mr. Choi that I won't be leaving till he gives me tutoring sessions, too." _

Soobin gave a barely audible sigh.

"My gum, you've gotten us into quite the predicament."

Hueningkai whimpered, his face becoming more and more flushed by the passing seconds. He felt embarrassed. "I know.. and I'm sorry, let's just stop and–"

"Stop?" Soobin interrupted, quirking an eyebrow in an act of feigned confusion, "I'm  _ hard,  _ baby.. and you just want to  _ stop?" _

He abruptly thrusted into Hueningkai's tight hole, earning a startled moan from the latter. He quickly covered his mouth with a pair of shaky hands so as to not let anymore lewd sounds escape.

(normally, hueningkai wouldn't mind being loud. but right now, his best friend was outside the door– and he was the  _ last  _ person who he'd  _ ever  _ want this secret to spill out to– especially since he knew just how much of a law abiding brat taehyun was.)

(well, as law abiding as a high school student could be– but you get the point.)

"H-hyung," Hueningkai panicked, "what are you  _ doing?" _

"Just keep quiet," Soobin responded, biting his lips as he dug his fingers into Hueningkai's squishy ass before swiftly striking his hand down upon his right cheek.

"Ah–!"

_ "Mr. Choi?"  _ Taehyun spoke up again, _ "You ok in there? Did you hit yourself or something?" _

Soobin rubbed soothing circles onto Hueningkai's bare skin, basking in the little whines and whimpers he was trying so hard to hide.

"I'm fine, Taehyun." He replied, pulling out of Hueningkai's ass, spreading his cheeks just enough to admire his pink, puckered hole and the way it looked so pretty and innocent, before slowly thrusting his cock back into the younger boy again, smirking as he watched Hueningkai tremble and shudder beneath him– watched as he seemed to be trying his absolute  _ best  _ to stifle his moans, a sense of pride filling Soobin as he continued to take note of the pathetic yet endearing scene unfolding right in front of him.

Hueningkai's thighs were shaking, his arms were trembling, and he kept clenching around Soobin's dick. He was on the verge of cumming, Soobin could tell– as if his scrunched up nose and quivering lips weren't enough proof of the bold claim.

_ "You sure?"  _ Taehyun continued, _ "It sounded like it hurt." _

Soobin merely let loose a long, drawn out sigh– pulling out of Hueningkai just to slam himself back in again.

_ "Mmh!"  _ Hueningkai moaned, the sound dampened by his hands. 

He couldn't help but arch his back every time he felt Soobin's cock hit  _ that  _ spot, vision turning blurry and hazy for a jumbled up second in the midst of the overwhelming pleasure he was experiencing.

It was too much, and the realization of the situation he'd managed to get himself into was finally starting to sink in because having sex with your teacher in an empty classroom was risky enough as it was– but to do it while your best friend was standing  _ right outside? _

It was a surefire way to get caught, a one-way ticket to the principal's office, and a 100% guarantee that Soobin would lose his job. 

(but, regretfully so, that was  _ exactly _ what made it so exciting.)

Hueningkai slowly removed his hands from his mouth, reverting back to simply clawing at the desk beneath him as much as his blunt fingernails could. He wiggled his ass around, feeling Soobin's cock move alongside his teasing motions.

"Ah– h-hyung.." He mumbled, curling his toes as he felt Soobin press himself flush against Hueningkai's ass, burying his dick deep inside of him, halting his squirming. He sucked in a shaky breath, ears becoming flushed and cheeks blooming with a familiar warmth, "..mm– f-fuck me before Taehyunie comes in.."

Soobin just smiled, a content expression plastered onto his face as he spoke slowly; carefully. 

"Anything for you, my gum."

Soobin dug the tips of his fingers into the sides of Hueningkai's slim waist, dug them deep enough to ensure bruises painted onto his body should Hueningkai ever decide to take off his shirt and examine his pale torso.

He began thrusting slowly at first– making sure Hueningkai got used to how his cock was stretching his tight hole, cute little moans accompanying each and every buck of Soobin's hips, before picking up the pace to the point where he was positive, _extremely_ so, that Taehyun– poor, oblivious Taehyun– could hear the dirty sound of skin slapping against skin echo throughout the classroom he was standing right outside of.

"T-too fast–!" Hueningkai choked out, an array of pretty little noises leaving him in the process. He no longer cared if his friend could hear him or not as it was the least of his worries. Right now, all he could really think about was just how  _ full  _ he felt with his teacher's cock buried deep inside of him, hitting all the right spots that made his knees buckle and his thighs tremble.

Soobin picked up the pace, wanting to hear more of Hueningkai's noises, wanting to hear more of his incoherent blabbering and slurred words, wanting to see the ethereal way tears were beginning to prickle in his waterline, eyes glossy and ready to shed tears because Soobin's dick just felt _so fucking good._

"So pretty for me, Hueningie.." Soobin murmured, throwing his head back as he gripped Hueningkai's waist much tighter than before, pounding into the younger boy like if he wasn't risking being on the verge of losing his job and all his credibility should he be caught by Taehyun.

Soobin groaned, feeling Hueningkai tighten around him every now and then, feeling his tight hole eating up his cock deliciously. His moans were broken and desperate– and although Hueningkai sounded borderline pathetic, he was letting out the sweetest sounds Soobin's ears had ever had the pleasure of hearing. 

Maybe he was simply just too enamored with this particular doe-eyed student, but the amount of things he was doing to his heart– unknowingly, at that– was quite alarming.

Hueningkai moaned, snapping Soobin out of his thoughts as he rocked his hips back into his teacher's cock, meeting his thrusts. He was panting and sweaty, flushed and dazed; he was high off of Soobin's dick.

_ "Hyuuuung.."  _ Hueningkai whined, "s-slow down please, my tummy feels weird.."

_ "Hueningie? Are you ok?"  _ Taehyun spoke up after a couple minutes of keeping quiet,  _ "You sound.."  _ he searched for the proper word, mentally sifting through numerous terms before one finally clicked,  _ "..off." _

"What are you waiting for?" Soobin whispered, droplets of sweat trailing down the sides of his temples. He continued thrusting into Hueningkai, continued to watch the way his frail body jerked forward with each and every powerful buck of his hips, lewd noises escaping his plump lips; he swore he could spot drool dribbling out of the side of his mouth, "aren't you gonna answer your friend?"

_ "Hueningieeeee.."  _ Taehyun called out once more and  _ god _ did Hueningkai just want him to shut up,  _ "answer me– are you ok?" _

"I'm fine!" Hueningkai's voice cracked. It was shaky and unstable, but it was to be expected when he was in the midst of getting the daylights fucked out of him by his own teacher, "I'm– I'm ok, Taehyunie.." he reiterated.

Soobin heard a perplexed  _ "hm"  _ come from outside his classroom door, and he could only assume that Taehyun was growing more and more suspicious of what they were actually doing because Taehyun was sure– extremely so, at that– that Soobin didn't actually offer any tutoring sessions, and that whatever Hueningkai was doing with him right now was probably  _ far _ from something as innocent as a  _ tutoring session. _

Soobin opted in pushing that trivial thought to the side, focusing more on just how  _ tight  _ Hueningkai felt. The faster he fucked him, the louder he got– and the harder it became to keep himself from cumming.

"Baby.." He whispered, thrusts becoming sloppy and uncoordinated in the process, grunts and low groans filling up the air around him much more frequently than before, mixing in with some of Hueningkai's own, "you're so– fuck, you're so tight.."

Hueningkai whined at the comment, simply continuing to match his hips with Soobin's thrusts as best as he could, starting to feel a familiar warmth pool in his lower abdomen and suddenly all he could see were  _ stars. _

He cried out for Soobin, voice wavering and desperate, knees threatening to buckle beneath him as his dick twitched and immediately released it's load in hot spurts, staining the antique piece of furniture he was laying atop of.

"S-soobin hyu- _ ung _ –  _ mmh!"  _ He clenched his thighs together, mouth gaped open as he felt the overwhelming sensation of his orgasm hit him, jolts of pleasure coursing throughout his body as he shamelessly moaned in ecstasy.

Soobin halted his thrusts, buried balls deep inside Hueningkai as he felt him become  _ painfully  _ tight– and before he knew it, he was cumming alongside the young boy, coating the inside of his walls with an array of deep, velvety moans mixing in with Hueningkai's high pitched ones.

Hueningkai's legs trembled; they shook and felt like jelly, feeling stuffed to the hilt by his teacher's cock– full of his cum like the slut that he was. He couldn't help but whine, trying his best to squirm and adjust himself to Soobin's length but to no avail– the older man had him gripped tightly by his waist; he wasn't going anywhere.

"Fuck.." Soobin breathed, his dick throbbing inside Hueningkai's hole, "you always make hyung feel so good, baby."

Hueningkai whimpered at the praise, sniffling and wiping away trails of tears that'd managed to cascade down his squishy cheeks in the midst of Soobin's ruthless fucking.

_ "Are you done yet, Hueningie?"  _ Taehyun spoke up for the nth time, and Hueningkai would've been annoyed had he not been too busy drooling all over Soobin's desk.

He gave a broken  _ "what?"  _ as a response, still feeling quite drunk off of his teacher's dick.

_ "Are you done having sex,"  _ Taehyun deadpanned, and it came out sounding more like a statement than a question,  _ "with Mr. Choi, I mean." _

The atmospheric change that followed immediately after Taehyun's bold choice of words was  _ terrifying. _

_ "Don't worry,"  _ He said, a smirk snaking its way into his tone of voice,  _ "I'll keep your secret as long as you tell him to give me good grades, too." _

_ "I don't wanna have sex with him though, if that's what you were thinking,"  _ Taehyun continued, almost biting his tongue in the midst of doing so,  _ "I already do that enough with the  _ **_other_ ** _ Mr. Chois." _

Hueningkai's eyes went wide.

"..Huh?"

_ "You heard me,"  _ He tsked, _ "how else do you think I got my valedictorian spot? Certainly not from studying, that's for sure." _

Soobin let out a sigh of relief, chuckling to himself as he ran a hand through his damp hair, "So  _ that's  _ why Yeonjun and Beomgyu always talk about Taehyun.. here I thought they just had favorites." he mumbled, shaking his head as he bit his lips and slapped Hueningkai's ass.

Hueningkai shrieked, a lewd moan following immediately after, "H-hyung!" he stuttered, cheeks adorning a cherry red color for the nth time.

"What? There's nothing to hide, Hueningie. Not anymore, at least." He looked to the side, raising his voice ever so slightly. "Taehyun– I'll give you a free hundred tomorrow on a test grade if you leave me and Hueningkai alone."

A small gasp was heard from outside the classroom door, followed by a tiny  _ "really?" _

Soobin chuckled, nodding his head even though he knew Taehyun couldn't see it, "Yes, really."

The sound of shoes walking away from Soobin's classroom gradually became more and more faint, before he assumed that Taehyun had finally left, leaving him and Hueningkai alone  _ at last. _

"Hueningkai," He spoke, and the way his voice was so low and soothing made Hueningkai want to  _ melt,  _ "what do you think about a round two?"

Hueningkai bit his lips, cock twitching at the suggestion, wiggling his ass onto Soobin's dick as he let out the prettiest moans and whimpers.

"I'd love to, hyung."

**Author's Note:**

> oh wow it's been so long since i've uploaded that i feel sorta nervous posting this AHAH but nonetheless sookai student teacher relationship for the win 😼💞💘💝
> 
> [cc](https://curiouscat.qa/yellowjun)  
> 
> 
> [twitter](https://twitter.com/yeIIowjun?s=09)


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